166. Unit Testing with nose2

Snippet 1: Basic Test Case with nose2

import unittest

class TestBasic(unittest.TestCase):
    def test_addition(self):
        self.assertEqual(1 + 1, 2)

# Run using nose2
# Command: nose2

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Snippet 2: Testing a Function

import unittest

def add(a, b):
    return a + b

class TestMathOperations(unittest.TestCase):
    def test_add(self):
        self.assertEqual(add(2, 3), 5)
        self.assertEqual(add(-1, 1), 0)

# Run using nose2

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Snippet 3: Test Case with Setup and Teardown

import unittest

class TestSetupTeardown(unittest.TestCase):
    def setUp(self):
        self.data = [1, 2, 3]
    
    def tearDown(self):
        self.data = None
    
    def test_length(self):
        self.assertEqual(len(self.data), 3)

# Run using nose2

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Snippet 4: Testing Exceptions

import unittest

def divide(a, b):
    if b == 0:
        raise ValueError("Division by zero")
    return a / b

class TestExceptions(unittest.TestCase):
    def test_divide_by_zero(self):
        with self.assertRaises(ValueError):
            divide(10, 0)

# Run using nose2

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Snippet 5: Skipping Tests

import unittest

class TestSkipping(unittest.TestCase):
    @unittest.skip("Skipping this test case")
    def test_skipped(self):
        self.assertTrue(False)

# Run using nose2

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Snippet 6: Parameterized Tests Using unittest.TestCase

import unittest

def multiply(a, b):
    return a * b

class TestParameterized(unittest.TestCase):
    def test_cases(self):
        test_data = [(2, 3, 6), (0, 5, 0), (-1, 2, -2)]
        for a, b, expected in test_data:
            with self.subTest(a=a, b=b):
                self.assertEqual(multiply(a, b), expected)

# Run using nose2

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Snippet 7: Grouping Tests in a Test Suite

import unittest

class TestMath(unittest.TestCase):
    def test_add(self):
        self.assertEqual(1 + 2, 3)

    def test_subtract(self):
        self.assertEqual(5 - 3, 2)

if __name__ == "__main__":
    unittest.TestLoader().discover('.')

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Snippet 8: Mocking in Tests

import unittest
from unittest.mock import MagicMock

class TestMock(unittest.TestCase):
    def test_mock(self):
        mock_function = MagicMock(return_value=42)
        result = mock_function()
        self.assertEqual(result, 42)

# Run using nose2

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Snippet 9: Asserting on Lists

import unittest

class TestListOperations(unittest.TestCase):
    def test_list_equality(self):
        self.assertListEqual([1, 2, 3], [1, 2, 3])

# Run using nose2

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Snippet 10: Testing File Operations

import unittest
import os

class TestFileOperations(unittest.TestCase):
    def test_file_creation(self):
        with open("test.txt", "w") as f:
            f.write("Hello, world!")
        self.assertTrue(os.path.exists("test.txt"))
        os.remove("test.txt")

# Run using nose2

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